Use of Familiar Things in the Design of Interfaces

Icons are used increasingly in interfaces because they are compact
"universal" pictographic representations of computer functionality and
processing. Animated icons can bring to life symbols representing complete
applications or functions within an application, thereby clarifying their
meaning, demonstrating their capabilities, and even explaining their method of
use. To test this hypothesis, we carried out an iterative design of a set of
animated painting icons that appear in the HyperCard tool palette. The design
discipline restricted the animations to 10 to 20 second sequences of 22x20
pixel bit maps. User testing was carried out on two interfaces - one with the
static icons, one with the animated icons. The results showed significant
benefit from the animations in clarifying the purpose and functionality of the
icons.

Walkthroughs

Traditional programming language design has focussed on efficiency and
expressiveness, with minimal attention to the ease with which a programmer can
translate task requirements into statements in the language, a characteristic
we call "facility." The programming walkthrough is a method for assessing the
facility of language design before implementation. We describe the method and
its predictions for a graphical programming language, ChemTrains. These
predictions are contrasted with protocols of subjects attempting to write their
first ChemTrains program. We conclude that the walkthrough is a valuable aid
at the design stage, but it is not infallible. Our results also suggest that
it may not be enough for programmers to know how to solve a problem; they must
also understand why the solution will succeed.

The Use of Video in Remote Group Work

We describe two systems that use interactive computer-controlled video for
shared awareness and casual communication. Polyscope lets users monitor a
large number of video sources simultaneously. Observers are provided with a
window containing a collection of frame-grabbed bitmap images or animations.
These images can be used to access additional video services, such as
videophone. Vrooms is a follow-on system, which employs a strong spatial
metaphor. Users can enter and leave virtual rooms. Once in a virtual room,
users can see and be seen by all the other occupants, and have easy access to
other video, audio, and text-based communication tools.

Multimedia Authoring Systems

Both theory and data suggest that richer, more informal, and more
interactive media should be better suited for handling the more complex,
equivocal, and emotional aspects of collaborative tasks. To test this
hypothesis, we constructed an experiment in which participants were required to
make either written or spoken annotations to a document to help a fictional
co-author revise it. We seeded relatively error-free texts with errors of
different scope. The results provide strong evidence that a richer -- in the
sense of a more expressive -- medium is especially valuable for the more
complex, controversial, and social aspects of a collaborative task. Subjects
stated that they preferred to use voice to comment on higher-level issues in a
document and to use text to deal with lower-level problems of spelling and
grammar. When subjects' annotation modalities were restricted, using written
annotations led them to comment on more local problems in the text, while using
speech led them to comment on higher level concerns. When they did use written
annotations to comment on global problems, they were less successful than when
they used spoken annotations. Finally, when they offered spoken annotations,
they were more likely to add features, such as personal pronouns and
explanation, that made their comments more equivocal and socially
communicative. These results indicate the uses to which systems that provide
voice annotation are likely to be put.

User Interface Management Systems

This article presents an abstract space of dimensions which characterize the
behavior of applications (i.e. functional cores) with regard to UIMS
components. These dimensions such as responsiveness, accessibility, and
instantiability, constitute a conceptual framework which captures the notion of
functional core in terms adequate for UIMS designers. The dimension space may
also be viewed as a requirements list for designing new UIMSs as well as a set
of criteria for evaluating existing UIMSs.

Programming by Demonstration

Eager is a Programming by Example system for the HyperCard environment. It
constantly monitors the user's activities, and when it detects an iterative
pattern, it writes a program to complete the iteration.
Programming by Example systems create generalized programs from examples
provided by the user. They are faced with the problem of how to display these
abstract procedures. Eager utilizes a new interface technique, called
anticipation, to show how it has generalized: when it detects a repetitive
activity, it highlights menus and objects on the screen to indicate what it
expects the user to do next. As users continue to perform their activity, they
will notice that the objects they are about to select have already been
highlighted by the system. When it becomes apparent that Eager knows how to
perform the task correctly, they can tell Eager to complete the task for them.
The use of anticipation allows Eager to interfere minimally with the users'
normal activities.

Group Use of Computing

An important issue in collaborative systems is the kind of sharing or
coupling among the various windows displaying a shared workspace. We have
developed a flexible coupling model that allows users to control several
aspects of the coupling among shared windows including which values in these
windows are coupled, when changes to these values are broadcast and received,
how "correct" a value must be before it is broadcast or received, which users
see the same view of a value, and whether a user can specify coupling
parameters for other users. In this paper, we argue that a collaborative
system must support flexible coupling, identify some of the issues in the
design of systems supporting flexible coupling, describe and illustrate our
approach to flexible coupling, and present conclusions and directions for
future work.

Information Retrieval

This paper describes the first phase of a project to create a desktop
information system for general users. The approach was to observe the
problems, needs, and practices of several groups of information users, and to
use these observations to drive the interface design of a prototype. In the
first section of the paper, we describe problems which arise in the use of a
relevance feedback system for information retrieval. In the second and third
sections, we look at the needs and practices of users of both electronic and
paper-based information systems. In the final section, we briefly describe the
resulting design.

Traditional information access systems generally assume that a
well-articulated query exists, and that once an object is found, it can be
readily understood. Although this assumption works for retrieving text
objects, in more complex domains, such as retrieving software objects for
reuse, queries must be incrementally constructed and support is needed for
comprehending what is retrieved. Therefore, information access methods need
support for query construction and relevance evaluation as an integral part of
the location process.
Two prototype systems are described for supporting this need: CODEFINDER for
query construction and EXPLAINER for explanations of program examples. These
systems interact to support the processes of locating and comprehending
software objects for reuse.

Large information spaces present several problems including information
overload. This research effort focuses on the domain of Usenet News, an open
access computer-based bulletin board system that distributes messages and
software. A conceptual framework is developed that shows the need for (a)
flexible organization of information access interfaces and (b) personalized
structure to deal with vocabulary mismatches. An operational innovative system
building effort (INFOSCOPE) instantiates the framework. In INFOSCOPE, users
can evolve the predefined system structure to suit their own semantic
interpretations. The approach taken by INFOSCOPE differs from other approaches
by requiring less up-front structuring by message senders.

Understanding Graphical Interfaces

This paper aspires to make three points: (1) that certain graphical
interfaces are especially easy to learn and use, (2) that special graphical
deduction / computation systems are possible, and (3) that perhaps points (1)
and (2) are intimately related, i.e., that graphical interfaces may be
especially useful because they engage special human graphical reasoning
processes.

Use of Familiar Things in the Design of Interfaces

Ecological approaches to psychology suggest succinct accounts of easily-used
artifacts. Affordances are properties of the world that are compatible with
and relevant for people's interactions. When affordances are perceptible, they
offer a direct link between perception and action; hidden and false affordances
lead to mistakes. Complex actions can be understood in terms of groups of
affordances that are sequential in time or nested in space, and in terms of the
abilities of different media to reveal them. I illustrate this discussion with
several examples of interface techniques, and suggest that the concept of
affordances can provide a useful tool for user-centered analyses of
technologies.

Sound

We designed an ecology of auditory icons which worked together to convey
information about a complex, demanding simulation task, and observed users
collaborating on it with and without sound. Our observations suggest that
audio cues can provide useful information about processes and problems, and
support the perceptual integration of a number of separate processes into one
complex one. In addition, they can smooth the transition between division of
labour and collaboration by providing a new dimension of reference. These
results suggest that auditory icons can play a significant role in future
multiprocessing and collaborative systems.

Group Use of Computing

CSCW research and groupware development represent converging interests from
two contexts of interactive systems development. Issues of group dynamics and
organizational impact have primarily been explored in the in-house development
of systems for organizations -- systems that support organizational goals.
Similar issues are now being encountered by researchers and developers with a
product development orientation who are seeking to support small groups. We
have not integrated effectively the interests, experiences and approaches
arising in these two development contexts. To do so, we have to go beyond what
is shared and explore the differences.

The Use of Video in Remote Group Work

In the following paper we discuss some findings of recent research
concerning the organisation of video mediated communication in collaborative
work in a dispersed, multi-media office environment. Based on the detailed,
naturalistic analysis of video-recordings of individuals collaborating on
various tasks through audio-visual links, we describe the ways in which the
technology transforms nonverbal and verbal conduct, introducing certain
asymmetries into the social interaction between users. It is argued that such
communicative asymmetries may facilitate, rather than hinder, certain forms of
collaborative work and provide a foundation for the emergence of new forms of
sociability in the work place.
What of the hands? We require, promise, call,
dismiss, threaten, pray, supplicate, deny, refuse,
interrogate, admire, number, confess, repent,
confound, blush, doubt, instruct, admire, number,
confess, repent, confound, blush, doubt, instruct,
command, incite, encourage, swear, testify,
accuse, condemn, absolve, abuse, despise, defy,
flatter, applaud, bless, humiliate, mock, reconcile,
recommend, exalt, entertain, congratulate,
complain, grieve, despair, wonder,
exclaim, .... There is not a motion that does not
speak and in an intelligible language without
discipline, and a public language that everyone
understands.

Montaigne 1952 pp. 215-216

Keywords: Multi-media, Video communication, Interaction analysis

Understanding Graphical Interfaces

Notepad computers promise a new input paradigm where users communicate with
computers in visual languages composed of handwritten text and diagrams. A key
problem to be solved before such an interface can be realized is the efficient
and accurate recognition (or parsing) of handwritten input. We present
techniques for building visual language parsers based on a new formalism,
constrained set grammars. Constrained set grammars provide a high-level and
declarative specification of visual languages and support the automatic
generation of efficient parsers. These techniques have been used to build
parsers for several representative visual languages.

Keywords: Notepad computers, Constraints, Parsing, Visual languages

Systems for Training

Programmable User Models (PUMs) are tools based on psychological theory that
enable interface designers to predict the usability of a proposed design. This
paper presents a variant in which the PUM, implemented in Soar and
incorporating the constraints of Display-based Task-Action Grammars, learns the
task-action mapping by being guided by the designer during performance. We
show that the more consistent and interactive the interface, the easier it is
for the designer to teach the PUM the necessary task-action mapping.

Practical Design Methods

User Interface Evaluation in the Real World: A Comparison of Four Techniques

A user interface (UI) for a software product was evaluated prior to its
release by four groups, each applying a different technique: heuristic
evaluation, software guidelines, cognitive walkthroughs, and usability testing.
Heuristic evaluation by several UI specialists found the most serious problems
with the least amount of effort, although they also reported a large number of
low-priority problems. The relative advantages of all the techniques are
discussed, and suggestions for improvements in the techniques are offered.

Programming

Program comprehension is a complex problem solving process. We report on an
experiment that studies expert programmers' comprehension behavior in the
context of modifying a complex PASCAL program. Our data suggests that program
comprehension is best understood as a goal-oriented, hypotheses-driven
problem-solving process. Programmers follow a pragmatic as-needed rather than
a systematic strategy, they restrict their understanding to those parts of a
program they find relevant for a given task, and they use bottom-up
comprehension only for directly relevant code and in cases of missing,
insufficient, or failing hypotheses. These findings have important
consequences for the design of cognitively adequate computer-aided software
engineering tools.

Virtual Reality

We describe a software architecture for virtual worlds, built on a base of
multiple processes communicating through a central event-driven user interface
management system. The virtual world's behavior is specified by a dialogue
composed of modular subdialogues or rule sets. In order to achieve high
flexibility, device remappability and reusability, the rule sets should be
written as independent modules, each encapsulating its own state. Each should
be designed according to its purpose in a conceptual hierarchy: it can
transform a specific device into a generic device, or transform a generic
device into an interaction technique, or, at the top level, map interaction
techniques to actions.

Understanding Graphical Interfaces

Despite the increasing importance of graphics in the design of information
systems, we have only a partial understanding of how people perceive and
process graphic information. This paper describes a computer program, UCIE,
that simulates graphical perception. The goal of the program is to model the
underlying perceptual and cognitive processes people use to decode information
from a graph. The model predicts reaction time from assumptions about the
logical sequence of eye fixations, STM capacity and duration limitations, and
the relative level of difficulty to acquire information in each glance. The
model summarizes a large body of empirical results and can be the core of an
expert advisor for the construction of graphs.

User Interface Design Process and Evaluation

We present the results of a survey designed to identify ways that human
factors engineers have been successfully involved in software projects.
Surveys describing successful and unsuccessful outcomes were returned by 14
human factors engineers and 21 software and documentation engineers at Hewlett
Packard. In addition to describing the type of involvement and techniques
used, respondents were also asked to define what they considered to be a
successful outcome and give their views on what factors contribute to success
or failure. The results of this study suggest ways in which the human
factors/R&D partnership can be more effective in current development scenarios.

Group Use of Computing

One of the properties of a user interface is that it both guides and
constrains the patterns of interaction between the user and the software
application. Application software is increasingly designed to be
"customizable" by the end user, providing specific mechanisms by which users
may specify individual preferences about the software and how they will
interact with it over multiple sessions. Users may thus encode and preserve
their preferred patterns of use. These customizations, together with choices
about which applications to use, make up the unique "software environment" for
each individual.
While it is theoretically possible for each user to carefully evaluate and
optimize each possible customization option, this study suggests that most
people do not. In fact, since time spent customizing is time spent not
working, many people do not take advantage of the customization features at
all. I studied the customization behavior of 51 users of a Unix software
environment, over a period of four months. This paper describes the process by
which users decide to customize and examines the factors that influence when
and how users make those decisions. These findings have implications for both
the design of software and the integration of new software into an
organization.

Keywords: Customization, Tailorability, Unix

Pointing, Gesture and Handwriting as Input Media

A Comparison of Input Devices in Elemental Pointing and Dragging Tasks

An experiment is described comparing three devices (a mouse, a trackball,
and a stylus with tablet) in the performance of pointing and dragging tasks.
During pointing, movement times were shorter and error rates were lower than
during dragging. It is shown that Fitts' law can model both tasks, and that
within devices the index of performance is higher when pointing than when
dragging. Device differences also appeared. The stylus displayed a higher
rate of information processing than the mouse during pointing but not during
dragging. The trackball ranked third for both tasks.

Keywords: Input devices, Input tasks, Performance modeling

Use of Familiar Things in the Design of Interfaces

Reaching Through Analogy: A Design Rationale Perspective on Roles of Analogy

A powerful way of reaching through technology is to use analogy to make the
technology transparent by exploiting the user's familiarity with other
situations. However, analogy has a number of roles in user interface design in
addition to the one of helping the user understand the system. In this paper
we consider some of these roles and their relationship to our Design Rationale
(DR) framework (MacLean et al., 1989). Our goals are to develop the DR
framework by exploring the implications of explicitly taking account of
analogy, and to articulate an account of the roles of analogy in design by
organising them around DR concepts.

Information Visualization

Tasks that involve large information spaces overwhelm workspaces that do not
support efficient use of space and time. For example, case studies indicate
that information often contains linear components, which can result in 2D
layouts with wide, inefficient aspect ratios. This paper describes a technique
called the Perspective Wall for visualizing linear information by smoothly
integrating detailed and contextual views. It uses hardware support for 3D
interactive animation to fold wide 2D layouts into intuitive 3D visualizations
that have a center panel for detail and two perspective panels for context.
The resulting visualization supports efficient use of space and time.

This paper proposes a concept for the user interface of information
retrieval systems called an information workspace. The concept goes beyond the
usual notion of an information retrieval system to encompass the cost structure
of information from secondary storage to immediate use. As an implementation
of the concept, the paper describes an experimental system, called the
Information Visualizer, and its rationale. The system is based on (1) the use
of 3D/Rooms for increasing the capacity of immediate storage available to the
user, (2) the Cognitive Co-processor scheduler-based user interface interaction
architecture for coupling the user to information agents, and (3) the use of
information visualization for interacting with information structure.

The task of managing and accessing large information spaces is a problem in
large scale cognition. Emerging technologies for 3D visualization and
interactive animation offer potential solutions to this problem, especially
when the structure of the information can be visualized. We describe one of
these Information Visualization techniques, called the Cone Tree, which is used
for visualizing hierarchical information structures. The hierarchy is
presented in 3D to maximize effective use of available screen space and enable
visualization of the whole structure. Interactive animation is used to shift
some of the user's cognitive load to the human perceptual system.

Special Purpose Interfaces

Complex tasks consist of many threads of activity to remember and
coordinate. Managing these threads is a significant part of problem solving.
Our research attempts to find ways to assist this process. In this paper we
present DETENTE, an object-oriented system to embed agendas in complex
application interfaces.

Remote Synchronous Collaboration

A media space is a system that uses integrated video, audio, and computers
to allow individuals and groups to work together despite being distributed
spatially and temporally. Our media space, CAVECAT (Computer Audio Video
Enhanced Collaboration And Telepresence), enables a small number of individuals
or groups located in separate offices to engage in collaborative work without
leaving their offices. This paper presents and summarizes our experiences
during initial use of CAVECAT, including unsolved technological obstacles we
have encountered, and the psychological and social impact of the technology.
Where possible we discuss relevant findings from the psychological literature,
and implications for design of the next-generation media space.

The Use of Video in Remote Group Work

An experiment was performed to examine predictions from Clark's contribution
theory of discourse. Pairs were asked to use a text-based synchronous
messaging system to solve a problem involving the layout of a bank.
Contribution theory suggests that in such text-only communication common ground
will be difficult to achieve. This was shown to be the case. A parallel
system, where participants could use a common report space in addition to the
messaging space, significantly reduced these problems. The implications for
design are discussed in terms of providing additional channels for
communicating the results of discussion separate from the conversation itself.

Keywords: Common ground, Cooperative work, Text-based communication

Remote Synchronous Collaboration

Managing a trois: A Study of a Multi-User Drawing Tool in Distributed Design
Work

A multi-user drawing tool was used by participants in a distributed design
exercise conducted in a multi-media working environment. The goal of the study
was to explore how observations from our earlier studies of shared drawing in
two-person design activity would hold up when three participants worked
together. Additionally, the study provided opportunities to contrast
video/audio connections with audio-only connections and to discover new
behaviors that emerge in the use of new technologies.
Participants successfully used the shared drawing system with no observed
difficulties attributable to the addition of a third user. Audio-only
connections appeared to adequately support this work activity, but details of
the participants' interactions in the exercise raised questions that deserve
further study. Finally, observations suggest that drawing tools such as the
one reported here may offer support for alternative forms of participation in
collaborative work.

User Interface Design Process and Evaluation

This paper describes PICTIVE, an experimental participatory design technique
that is intended to enhance user participation in the design process. PICTIVE
combines low-tech objects with high(er)-tech video recording. The low-tech
objects -- i.e., non-computer representations of system functionality -- are
intended to insure that all participants have equal opportunity to contribute
their ideas. The video recording makes record-keeping easy, reduces social
distance during the design session, and may give rise to informal video "design
documents." The session proceeds by a kind of brainstorming, with the low-tech
objects used to express each participant's ideas to the others. This paper
describes our initial experiences with the PICTIVE technique, informal analyses
about why the technique works, and several Bellcore projects and products to
which it has been applied.

Practical Design Methods

The last decade of research and practice in user interface design has given
us some good models for designing user interfaces. Getting input from users
early and continuously throughout the design process, using rapid prototyping
and iterative design techniques, and conducting formal usability testing are
now proven methods for assuring good user interfaces. In the real world,
however, we often work on projects where it is difficult to put these methods
into practice. In this paper we will describe some strategies for making the
best possible user interface design decisions given extremely tight schedules,
shifting market priorities, and other typical constraints.

Pointing, Gesture and Handwriting as Input Media

A gesture recognition method for Japanese sign language is presented. We
have developed a posture recognition system using neural networks which could
recognize a finger alphabet of 42 symbols. We then developed a gesture
recognition system where each gesture specifies a word. Gesture recognition is
more difficult than posture recognition because it has to handle dynamic
processes. To deal with dynamic processes we use a recurrent neural network.
Here, we describe a gesture recognition method which can recognize continuous
gesture. We then discuss the results of our research.

User Interface Management Systems

Many modern user interface development environments use constraints to
connect graphical objects. Constraints are relationships that are declared
once and then maintained by the system. Often, systems provide graphical,
iconic, or demonstrational techniques for specifying some constraints, but
these are incapable of expressing all desired relationships, and it is always
necessary to allow the user interface designer to write code to specify complex
constraints. The spreadsheet interface described here, called C32, provides
the programmer with the full power of writing constraint code in the underlying
programming language, but it is significantly easier to use. Unlike other
spreadsheets tools for graphics, C32 automatically generates appropriate object
references from mouse clicks in graphics windows and uses inferencing and
demonstrational techniques to make constructing and copying constraints easier.
In addition, C32 also supports monitoring and debugging interfaces by watching
values in the spreadsheet while the user interface is running.

Keywords: Constraints, Spreadsheets, User interface development tools

Programming by Demonstration

In text formatters such as troff, Scribe, and TEX, users write macro
procedures to specify the desired visual appearance. In
What-You-See-Is-What-You-Get text formatters, such as MacWrite and Microsoft
Word, the formatting is specified by directly manipulating the text. However,
some important functionality is lost in these systems since they are not
programmable. For example, if the user wants to change the formatting and
content of all the chapter headings or page headings, each one must be
individually edited. If they had been generated by macros, then editing the
macro definition would change them all at once. This paper describes the
design for a demonstrational text formatter that allows the user to directly
manipulate the formatting of one example, and then the system automatically
creates the macro by generalizing the example. This technique makes the
formatting for headers, itemized lists, tables, bibliographic references, and
many other parts of documents significantly easier to specify and edit.

Systems for Training

Animated demonstrations are real-time instantiations of computer-based
procedures. They appear to be a natural way of helping people learn direct
manipulation interfaces, yet we know little about their efficacy. Carefully
matched animated demonstrations, procedural textual instructions, and a
combination of demonstrations and spoken text were compared. The demonstration
groups were faster and more accurate when learning procedural tasks, but seven
days later, the text group was faster and as accurate when performing identical
and similar tasks. Apparently, the processing of animated demonstrations may
not be sufficient for retention and transfer of interface procedures. Even
with accompanying text provided, the simplicity of using demonstrations may
encourage mimicry and disregard of text.

Virtual Reality

Virtual reality systems using head-mounted displays and glove input are
gaining popularity but their cost prohibits widespread use. We have developed
a system using an 80386 IBM-PC (TM), a Polhemus 3Space Isotrak (TM), two
Reflection Technology Private Eye (TM) displays, and a Mattel Power Glove (TM).
For less than $5,000, we have created an effective vehicle for developing
interaction techniques in virtual reality. Our system displays monochrome wire
frames of objects with a spatial resolution of 720 by 280, the highest
resolution head-mounted system published to date. We have confirmed findings
by other researchers that low-latency interaction is significantly more
important than high-quality graphics or stereoscopy. We have also found it
useful to display reference objects to our user, specifically a ground plane
for reference and a vehicle containing the user.

Pointing, Gesture and Handwriting as Input Media

Notebook computers, using stylus input, are currently a hot topic among PC
manufacturers. Handwriting recognition may be an important component of such
systems, but only if everyday sloppy handwriting can be accommodated. If
recognizers require unnaturally neat or boxed character input, such systems may
fail in the marketplace. Neural nets have shown excellent performance at
handwriting recognition. I present three neural net approaches to recognizing
lines of English text: one using 2D image input, one using stroke sequence
input, and one using context to combine the outputs of the other two networks.
These networks can be combined to form a recognition engine that will handle
natural lines of handwritten English text, including handprint, cursive script,
and mixtures of both.

Keywords: Character recognition, Neural networks

Programming

A prime attraction of object-oriented programming languages is the
possibility of reusing code. We examine the support provided by Smalltalk to
programmers attempting to incorporate an existing class into a new design,
focussing on issues of usage examples, object-specific analysis, how-to-use-it
information, and object connections. We then describe a View Matcher for
reuse, a tool that documents reusable classes through a set of coordinated
views onto concrete usage examples; in three scenarios, we illustrate how the
tool addresses the issues raised in our analysis of reuse in Smalltalk.

Special Purpose Interfaces

Recognition errors complicate the assessment of speech systems. This paper
presents a new approach to modeling spoken language interaction protocols,
based on finite Markov chains. An interaction protocol, prescribed by the
interface design, defines a set of primitive transaction steps and the order of
their execution. The efficiency of an interface depends on the interaction
protocol as well as the cost of each different transaction step. Markov chains
provide a simple and computationally efficient method for modeling errorful
systems. They allow for detailed comparisons between different interaction
protocols and between different modalities. The method is illustrated by
application to example protocols.

Systems for Training

Two experiments examined the utility of a menu-based question-construction
help system as part of basic instruction for UNIX. The first experiment
indicated that novice or naive users have great difficulty formulating their
own questions; a menu-based interface that helps structure questions increased
question asking and improved performance during training. A second experiment
demonstrated that initial learning benefits more from "procedural" than from
"causal" questions. A retention test showed that "correct response" feedback,
when coupled with an appropriate problem-solving learning environment, can
produce performance comparable to that in the question asking conditions; such
feedback, however, did not provide equivalent understanding of the system.
These results are discussed in the context of user models of the system and the
potential role of constraint in designing question-asking systems.

User Interface Design Process and Evaluation

Maximal repeating pattern (MRP) analysis is a recently developed user
interface evaluation technique that uses an algorithm to analyze transcripts of
user sessions by detecting repeated user actions. Encouraged by results of an
initial study of the MRP technique, we conducted a study in which we evaluated
a simple prototype interface using both the MRP technique and observation.
Interface problems found by observation were also found by MRP analysis.
Although the MRP algorithm produced large amounts of data that an interface
evaluator had to analyze, we found that by mapping raw user inputs in the
transcripts into more abstract classes via prefiltering, we could perform more
useful MRP analyses.

Programming by Demonstration

Dance is a tool that facilitates direct manipulation, demonstrational
development of animations for the Tango algorithm animation system. Designers
sketch out target actions in a graphical-editing fashion, then Dance
automatically generates the code that will carry out those actions. Dance
promotes ease-of-design, rapid prototyping, and increased experimentation. It
also introduces a methodology that could be used to incorporate demonstrational
animation design into areas such as computer assisted instruction and user
interface development.

Remote Synchronous Collaboration

VideoWhiteboard is a prototype tool to support remote shared drawing
activity. It provides a whiteboard-sized shared drawing space for
collaborators who are located in remote sites. It allows each user to see the
drawings and a shadow of the gestures of collaborators at the remote site. The
development of VideoWhiteboard is based on empirical studies of collaborative
drawing activity, including experiences in using the VideoDraw shared drawing
prototype. VideoWhiteboard, enables remote collaborators to work together much
as if they were sharing a whiteboard, and in some ways allows them to work
together even more closely than if they were in the same room.

User Interface Management Systems

This paper proposes a new model which describes the presentation and
behaviour of user interfaces. The behaviour of the user interface is specified
as an event flow graph consisting of components as its nodes and the paths
through which events are sent as its edges. A meta-level function is
introduced to describe user interfaces whose constituent components change
through user interaction. The reusability of objects is augmented by
representing their presentation and behaviour as a connected subgraph of the
event flow graph. User interface development systems based on this model can
create the user interface under a totally visual environment.

Practical Design Methods

We studied the use of an evolving interface style book to evaluate the role
of such guidelines in the development of style-conforming interface designs.
Although the designs were judged to be generally conforming, study participants
had significant difficulty in interpreting the guidelines. Our designers were
manifestly task oriented and impatient with extraneous material. They depended
heavily on the pictorial examples, often to the exclusion of the accompanying
text. We conclude that dependency on guidelines should be minimized, and that
guidelines should be developed primarily to complement toolkits and interactive
examples, focussing on information intrinsically unavailable through those
vehicles.

User interface standards can be hard to use for developers. In a laboratory
experiment, 26 students achieved only 71% compliance with a two page standard;
many violations were due to influence from previous experience with
non-standard systems. In a study of a real company's standard, developers were
only able to find 4 to 12 actual deviations in a sample system, and three real
products broke between 7 and 12 of the 22 mandatory rules in the standard.
Designers were found to rely heavily on the examples in the standard and their
experience with other user interfaces.

Multimedia Authoring Systems

A new approach to achieving a natural-motion-picture dedicated multi-media
authoring system is proposed. The main point of this approach, discussed in
this paper, is that the user's environment or interface is improved to
encourage user's creativity, with image processing and recognition technology.
According to the discussion, a prototype motion picture authoring system that
has several image-processing functions is developed. The newly developed
functions include object extraction of the picture, semi-automatic
visualization of motion pictures structure, and certain descriptions of the
scene. Result of using the prototype shows the appropriateness of the proposed
approach.

Sound

A recent development in advanced interface technologies is the virtual
acoustic display, a system that presents three-dimensional auditory information
over headphones [20]. The utility of such a display depends on the accuracy
with which listeners can localize the virtual, or simulated, sound sources.
Synthesis of virtual sources involves the digital filtering of stimuli using
filters based on acoustic Head-Related Transfer Functions (HRTFs) measured in
human ear-canals. In practise, measurement of the HRTFs of each potential user
of a 3-D display may not be feasible. Thus, a critical research question is
whether listeners from the general population can obtain adequate localization
cues stimuli based on non-individualized filters.
In the present study, 16 inexperienced listeners judged the apparent spatial
location (azimuth and elevation) of wideband noisebursts that were presented
either over loudspeakers in the free-field (an anechoic or non-reverberent
environment) or over headphones. The headphone stimuli were synthesized using
HRTFs from a representative subject in a previous study [23]. Localization of
both free-field and virtual sources was quite accurate for 12 of the subjects,
2 showed poor elevation accuracy in both free-field and headphone conditions,
and 2 showed degraded elevation accuracy only with virtual sources. High rates
of confusion errors (reversals in judgements of azimuth and elevation) were
also observed for some of the subjects and tended to increase for the virtual
sources. In general, the data suggest that most listeners can obtain useful
directional information from an auditory display without requiring the use of
individually-tailored HRTFs, particularly for the dimension of azimuth.
However, the high rates of confusion errors remain problematic. Several
stimulus characteristics which may help to minimize these errors are discussed.

The Use of Video in Remote Group Work

We examined mediated communication using a shared electronic Whiteboard with
and without the addition of a speech channel. The 3 users were not co-present.
There were two major findings: (a) permanent media such as the Whiteboard
enable users to construct shared data structures around which to organise their
activity, and (b) this permanence allows users to abandon some (but not all) of
the turn-taking commonly used in spoken conversation and to organise their
activities in a highly parallel manner. With the addition of a speech channel,
people still used the Whiteboard to construct shared data structures that make
up the CONTENT of these communications, while speech was used for coordinating
the PROCESS of communication.

Panels

The current usefulness of voice recognition seems suspect given today's
level of commercial voice recognition technology. The panel will discuss what
improvements are necessary to make voice recognition an acceptable input medium
for general consumer applications.

On July 27, 1990 the participants in MCC's Advanced Computer Technology
Program decided to terminate MCC's Human Interface Laboratory. This panel will
present the technical and organizational lessons learned in the rise and fall
of MCC's Human Interface Laboratory.

Modelling User, System and Design: Results of a Scenarios Matrix Exercise

This panel will discuss the results of an exercise aimed at investigating
how various modelling approaches from Cognitive Science and Software
Engineering can be integrated into HCI design. Each panelist will outline
their approach and present their approach's performance on two agreed upon
design scenarios.

Interface and Narrative Arts: Contributions from Narrative, Drama, and Film

This panel will explore both theoretical and practical contributions from
the disciplines of narrative, drama, and film to the field of interface design.
Example applications in information retrieval, art, education, simulation,
entertainment, and programming will be explored.

Case studies will be used to show how and where various expressive "artists"
do or do not use technology in their work place. The culmination of this panel
will be made in the form of a multi-media presentation created by the panelists
during the conference.

Participatory Design in Britain and North America: Responses to the
"Scandinavian Challenge"

This panel will focus on participatory design work conducted outside
Scandinavia. Each panelist will focus on what accommodations were required in
participatory design techniques to meet the needs of British and North American
environments. Panelists will also discuss accommodations that occurred in
these environments in response to experiences with participatory design.

A "demonstrational interface" watches while the user executes conventional
direct manipulation actions, creating a general abstraction from the specific
examples. The panel will discuss how demonstrational interfaces can be used,
and when and whether they will become more common.

This panel will provide an opportunity to hear attorneys and members of the
CHI community debate the pros and cons of "strong" copyright protection for
user interfaces to computer programs. The lawyer debaters will discuss some of
the judicial decisions that have been issued since the first CHI legal debate
in 1989.

This panel will examine the potential of artifact theory to deliver usable
designs in contention with two rival theories, the HCI conception of
engineering, and cognitive modelling. The aim will be to explore how well
artifact theory and alternative approaches can deliver good design and the
contribution the theory makes to the process and product of design.

Special Presentations

Ethical Issues in the Use of Video: Is it Time to Establish Guidelines?
(SIGCHI Discussion Forum)

Researchers and designers increasingly use video to obtain information about
how people interact with technology. This session provides a forum for
discussion: to identify ethical issues, learn from invited guests about
existing practice in other fields, and determine whether or not the
Human-Computer Interaction community should develop its own set of guidelines
for the ethical use of video.

FRIEND21 is a Japanese national project to develop the interface
architecture for computer machinery for the 21st century information
environment. FRIEND21 stands for Future Personalized Information Environment
Development. The member companies consist of three different industrial
groups: computer manufacturers, home electronics companies, and publishing or
printing companies. FRIEND21 is proposing a new design concept for
constructing the human interface. This will be implemented using multiple
metaphors for people's direct engagement into the environment called Contextual
Metaphors and a new software architecture called the Agency Model.